Method for Modifying Surface Properties with Nanostructured Chemicals

ABSTRACT

A method of using metallized and nonmetallized nanostructured chemicals as surface and volume modification agents within polymers and on the surfaces of nano and macroscopic particulates and fillers. Because of their 0.5 nm-3.0 nm size, nanostructured chemicals can be utilized to greatly increase surface area, improve compatibility, and promote lubricity between surfaces at a length scale not previously attainable.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.12/787,145 filed May 25, 2010, which is a continuation of U.S. patentapplication Ser. No. 11/641,543 filed Dec. 18, 2006 (now U.S. Pat. No.7,723,415), which claims the benefit of U.S. Provisional PatentApplication Ser. No. 60/751,362 filed Dec. 16, 2005, and is acontinuation-in-part of U.S. patent application Ser. No. 11/354,583filed Feb. 14, 2006 (abandoned), which claims the benefit of U.S.Provisional Application Ser. No. 60/652,922 filed Feb. 14, 2005; and isa continuation-in-part of U.S. patent application Ser. No. 11/342,240filed Jan. 27, 2006 (now U.S. Pat. No. 7,638,195), which claims thebenefit of U.S. Provisional Patent Application Ser. No. 60/648,327 filedJan. 27, 2005; and is a continuation-in-part of U.S. patent applicationSer. No. 11/225,607 filed Sep. 12, 2005 (now U.S. Pat. No. 7,553,904),which claims priority from U.S. Provisional Patent Application Ser. No.60/608,582 filed Sep. 10, 2004, and is a continuation-in-part of U.S.patent application Ser. No. 11/166,008 filed Jun. 24, 2005 (abandoned),which is a continuation of U.S. patent application Ser. No. 10/351,292,filed Jan. 23, 2003 (now U.S. Pat. No. 6,933,345), which claims priorityfrom U.S. Provisional Patent Application Ser. No. 60/351,523, filed Jan.23, 2002, and is a continuation-in-part of U.S. patent application Ser.No. 09/818,265, filed Mar. 26, 2001 (now U.S. Pat. No. 6,716,919), whichclaims priority from U.S. Provisional Patent Application Ser. No.60/192,083, filed Mar. 24, 2000. The disclosures of the foregoingapplications are incorporated herein by reference.

FIELD OF THE INVENTION

This invention relates generally to methods for enhancing the bulk andsurface properties of a polymer through use of POSS nanostructuredchemicals as dispersion aids, surface modifiers, and interfacialfriction modifiers.

BACKGROUND OF THE INVENTION

It is common practice to modify particulates of polymer, organic,inorganic, man-made or natural origin materials with silane couplingagents, surfactants, polymeric coatings, chemical oxidation treatments,chemical reduction treatments, hot and cold treatments, and radiationexposures in attempts to alter the surface properties of the particlewith itself or with a secondary material, or to improve its dispersivecharacteristics.

Prior art associated with particulates, coatings, and processingtechniques has not been able to precisely control particulate andmaterial surface properties and surface-surface interactions at the 1 nmto 50 nm level. Therefore, a need exists for surface modification agentsand techniques to provide such control.

SUMMARY OF THE INVENTION

The present invention describes methods of dispersing particulates intoa polymer by controlling its surface properties at the nanoscopic levelwith the use of nanostructured chemicals. The method is highly desirablefor the creation of chemical masterbatches. This invention also teachesa method of controlling the surface and interfacial properties ofpolymeric, metallic, ceramic, and surfaces derived from natural,man-made or biological materials by controlling their nanoscopic surfacetopology, surface area, and associated volume via nanostructuredchemicals. Such surface control can be applied in both remedial andoriginal manufacturing.

The invention solves the problem of dispersing nano and macroscopicparticulates at high concentrations within a polymer matrix. Thesolution is enabled uses nanostructured chemicals as dispersion aids andsurface modifying agents within polymeric materials and on particulatesurfaces. The invention also provides a means for reducing the frictionof surfaces through the use of the same nanostructured chemicals asinterfacial modifiers.

The use of POSS nanostructured chemicals for control of particulatedispersion in polymers is useful for the preparation of highlyconcentrated particulate masterbatches. The purpose of the masterbatchis to provide performance enhancing additive concentrates in an easilydilutable form. Masterbatches are desired by formulators, molders, andpolymer converters as they provide a convenient method of increasing thevalue of common plastics and are lower-cost to ship than a fully dilutedproduct. The ability to increase the concentration, complexity, number,and type of additives that can be incorporated into a masterbatchenables additional functionality and further increases value.

Combination of three primary material are preferred for masterbatchcompositions: (1) POSS nanostructured chemicals, POMS metallizednanostructured oligomers, or metal containing nanostructured polymers;(2) polymers or polymer/monomer combinations including traditionalamorphous polymer systems such as acrylics, carbonates, epoxies, esters,silicones, polyolefins, polyethers, polyesters, polycarbonates,polyimides, polyamides, polyurethanes, phenolics, cyanate esters,polyureas, resoles, polyanalines, fluoropolymers, and silicones andpolymers containing functional groups; traditional semicrystalline andcrystalline polymer systems such as styrenics, amides, nitriles,olefins, aromatic oxides, aromatic sulfides, and esters; or ionomers ortraditional rubbery polymer systems derived from hydrocarbons andsilicones; and (3) nanoscopic and macroscopic particulates includingmetals, metal alloys, oxides, ceramic, ceramic alloys, microtubes,nanotubes, inorganic, organic, and any particulate of man-made ornatural origin.

The nanostructured chemical can be utilized to surface functionalize aparticle prior to or during masterbatch mixing. It can be added to thepolymer followed by addition of the particulate filler or can be addedsimultaneously with the polymer and filler in a sequence that providesthe most desirable performance and economic advantages.

Preferably, the process of particulate dispersion occurs by combiningtogether the components of interest and effecting the surface andinterfacial modification through mixing. All types and techniques ofblending, and mixing including melt blending, dry blending, grinding,milling, solution blending, reactive and nonreactive mixing are alsoeffective.

In addition, because of their chemical nature, POSS nanostructuredchemicals can be tailored to show compatibility or incompatibility withnearly all polymer, biological, organic, and inorganic systems. Theirphysical size in combination with their tailorable compatibility enablesnanostructured chemicals to be selectively incorporated into plastics,and to control the dynamics of coils, blocks, domains, and segments, andsubsequently favorably impact a multitude of physical properties. Theproperties most favorably improved are time dependent mechanical andthermal properties such as viscosity, friction, solubility, dispersion,heat distortion, creep, shrinkage, compression set, modulus, hardness,abrasion resistance, electrical resistance, electrical conductivity,radiation absorption, luminescence, emissivity, degree of cure,biological compatibility and biological function. In addition tomechanical properties, other physical properties that are favorablyimproved include thermal conductivity and electrical conductivity, fireresistance, and gas barrier and gas and moisture permeation properties,which are selectively controlled depending on cage size, composition andhomogeneity of distribution.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates the representative volume contributions of a 1.5 nmPOSS molecule;

FIG. 2 illustrates the impact of surface area relative to weight %loading of POSS;

FIG. 3 illustrates the volume contribution relative to weight % loadingof POSS;

FIG. 4 illustrates representative examples of POSS nanostructuredchemicals;

FIG. 5 illustrates different surface topology for cages bound to asurface by one or three reactive groups;

FIG. 6 illustrates the use of a nanostructured chemical to increase thesurface area of a particle;

FIG. 7 illustrates the use of a nanostructured chemical to decrease theamount of surface in contact with a projectile particle;

FIGS. 8( a) and 8(b) illustrate the use of nanostructured chemicals toincrease the brightness of TiO₂ dispersions in polypropylene. FIG. 8( a)is a dispersion of polypropylene containing 5 wt % SO1450 and 1 wt %nanoscopic TiO₂. FIG. 8( b) is a dispersion of polypropylene with 1 wt %nanoscopic TiO₂;

FIG. 9 is a transmission electron micrography comparison of (A) 5 wt %SO1450 dispersed in polypropylene, (B) 100 nm average diameter ofnano-TiO₂ dispersed in polypropylene at 1 wt % level, and (C) 50 nmaverage diameter of nano-TiO₂ dispersed in polypropylene containing 5 wt% SO1450 and 1 wt % nano-TiO₂;

FIG. 10 illustrates the surface of a polypropylene control; and

FIG. 11 illustrates the surface of a 10% MS0825 POSS/polypropyleneformulation.

DEFINITION OF FORMULA REPRESENTATIONS FOR NANOSTRUCTURES

For the purposes of understanding this invention's chemical compositionsthe following definition for formula representations of PolyhedralOligomeric Silsesquioxane (POSS), Polyhedral Oligometallosesquioxane(POMS) and Polyhedral Oligomeric Silicate (POS) nanostructures is made.

Polysilsesquioxanes are materials represented by the formula[RSiO_(1.5)]_(∞) where ∞ represents molar degree of polymerization andR=represents an organic substituent (H, siloxide, siloxy, cyclic orlinear aliphatic or aromatic groups that may additionally containreactive functionalities such as alcohols, esters, amines, ketones,olefins, ethers or halides). Polysilsesquioxanes may be eitherhomoleptic or heteroleptic. Homoleptic systems contain only one type ofR group while heteroleptic systems contain more than one type of Rgroup. As a special case R may also include fluorinated organic groups.

POSS, POMS, and POS nanostructure compositions are represented by theformula:

[(RSiO_(1.5))_(n)]_(Σ#) for homoleptic compositions

[(RSiO_(1.5))_(n)(R′SiO_(1.5))_(m)]_(Σ#) for heteroleptic compositions(where R≠R′)

[(RSiO_(1.5))_(n)(RXSiO_(1.0))_(m)]_(Σ#) for functionalized heterolepticcompositions (where R groups can be equivalent or inequivalent)

[(RSiO_(1.5))_(n)(RSiO_(1.0))_(m)(M)_(j)]_(Σ#) for heterofunctionalizedheteroleptic compositions

In all of the above R is the same as defined above and X includes but isnot limited to OH, Cl, Br, I, alkoxide (OR), acetate (OOCR), peroxide(OOR), amine (NR₂), isocyanate (NCO), and R. The symbol M refers tometallic elements within the composition that include high and low Zmetals including s and p block metals, d and f block transition,lanthanide, actinide metals, in particular, Al, B, Ga, Gd, Ce, W, Ni,Eu, U, Y, Zn, Mn, Os, Ir, Ta, Cd, Cu, Ag, V, As, Tb, In, Ba, Ti, Sm, Sr,Pt, Pb, Lu, Cs, Tl, and Te. The symbols m, n and j refer to thestoichiometry of the composition. The symbol Σ indicates that thecomposition forms a nanostructure and the symbol # refers to the numberof silicon atoms contained within the nanostructure. The value for # isusually the sum of m+n, where n ranges typically from 1 to 24 and mranges typically from 1 to 12. It should be noted that Σ# is not to beconfused as a multiplier for determining stoichiometry, as it merelydescribes the overall nanostructural characteristics of the system (akacage size).

DETAILED DESCRIPTION OF THE INVENTION

The present invention recognizes that significant property enhancementscan be realized by the modification of particulate and polymer surfaceswith nanostructured chemicals. This greatly simplifies surfacemodification since the prior art does not control surface area, volume,or nanoscopic topology, and does not function as interfacial controlagents nor as alloying agents within polymer morphology or betweendissimilar materials.

The prior art is deficient in recognizing and establishing control overnanoscopic surface features. The present invention demonstrates thatproperties such as dispersion, viscosity, surface energy, lubricity,adhesion, and stain resistance can be easily and favorably controlledthrough use of nanostructured chemicals at material surfaces andinterfaces. Properties most favorably improved are time dependentmechanical and thermal properties such as particle dispersion,dispersion stability, heat distortion, creep, compression set, strength,toughness, visual appearance, feel, and texture, shrinkage, modulus,hardness and abrasion resistance, impact resistance, fire resistance,shrinkage reduction, expansion reduction, adhesion, lubricity,conductive, dielectric, capacitive properties, degree of cure, rate ofcure, radiation absorptive properties and biological activity. Inaddition other physical properties are favorably improved, including gasand moister permeability, paint, print, film and coating properties.

The fundamental premise behind surface modification in this invention isunderpinned mathematically through computation of the surface area andvolume contribution provided at various loadings of 1 nm sphericalnanostructured chemical particles either into or onto a material.Computation reveals that as a particle becomes smaller it contributesmore surface area and more volume as a wt % of its incorporation into amaterial than would larger particles (see FIGS. 1-3). The net effect isthat even small loadings of sufficiently small nanoparticles canultimately dominate the surface characteristics of a material. The newsurface provided by nanomodification can be utilized to either decreasesurface roughness by filling-in surface defects or can increase surfaceroughness by creating more surface. Furthermore, it can be utilized toeither increase or decrease the surface-surface interaction between twoor more materials by making their surfaces smoother or rougher. Thematerial surfaces can be similar or dissimilar, and of man-made or ofnatural or biological origin.

Practical applications of this invention require the use of nanoscopicparticulate-like entities. Most desirably, such particles would have aknown and precise chemical composition, rigid three dimensional shape,controllable diameter, and controllable surface chemistry.Nanostructured chemicals meet such requirements and are preferablyemployed in this invention.

Nanostructured chemicals are best exemplified by those based on low-costPolyhedral Oligomeric Silsesquioxanes (POSS) and Polyhedral OligomericSilicates (POS) and Polyhedral Oligometallosesquioxanes (POMS). FIG. 4illustrates some representative examples of monodisperse POSSnanostructured chemicals. However, logical extensions of nanoscopicchemicals include carboranes, polyoxometallates, and POMS, and are alsocontemplated in this invention. POMS are nanostructured POSS chemicalsthat contain one or more metals inside or outside the central cageframework. In certain instances, cages may contain more than one metalatom, or more than one type of metal atom or even metal alloys in or onthe cage.

POSS nanostructured chemicals contain hybrid (i.e. organic-inorganic)compositions and cage-like frameworks that are primarily comprised ofinorganic silicon-oxygen bonds which may also contain one or more metalatoms bound to the cage. In addition to the metal and silicon-oxygenframework, the exterior of a nanostructured chemical is covered by bothreactive and nonreactive organic functionalities (R), which ensurecompatibility and tailorability of the nanostructure with othersubstances. Unlike particulate fillers, POSS nanostructured chemicalsdissolve into polymers and solvents and exhibit a range of meltingpoints from −40° C. to 400° C.

POSS nanostructured chemicals bearing metal atoms (POMS), silanols,alcohols, amines or other polar groups are preferably utilized asdispersion and surface modification agents because they can chemicallyinteract and even permanently bond to the surface of silica, metallic orpolymer particles while nonreactive groups on the cage can compatibilizethe surface toward a secondary material or secondary surface. Thechemical nature of POSS nanostructured chemicals also renders theirdispersion characteristics to be governed by the Gibbs free energy ofmixing equation (ΔG=ΔH−TΔS) rather than kinetic dispersive mixing as forinsoluble particulates. Thus, the ability of POSS to interact with asurface through Van der Waals interactions, covalent, ionic, or hydrogenbonding can be utilized to chemically, thermodynamically, andkinetically drive their dispersion and surface modification.Furthermore, since POSS cages are monoscopic in size, entropicdispersion (ΔS) is favored.

Each POSS nanostructured chemical also has a molecular diameter that canbe controlled through variation of cage size and the length of the cageR groups attached to the cage (typical range from 0.5 nm to 5.0 nm). Themolecular diameter is key to providing control over surface topology,surface area, and volume contributions in optimal formulations. Forexample, a cage bound to a surface by three silanol groups provides alower topological profile than a cage bound at one vertice (FIG. 5).

Additionally, the topological control that POSS cages offers can be usedadvantageously as bumps on a surface (FIG. 6). The resulting surfaceroughness will increase the amount of bondable surface area and can beutilized to disrupt the interaction of filler particulates with eachother. It is well known that filler-filler interactions lead toself-quenching, agglomeration and inefficient dispersion of fillers andadditives. POSS greatly reduces filler-filler interactions and selfassociation by providing a nanoscopic spacer on the surface of particlesand between polymer chains.

Consequently, POSS surface modification can reduce surface friction bydecreasing the areal contact between two surfaces. Because POSS cagesare molecules they can also melt and thereby reduce friction throughnanoscopic surface lubrication and through isoviscous flow. This featureis particularly attractive for use in low friction fabrics, bandages,films, fabrics, tapes, and clothing.

The use of POSS to promote lower surface friction is beneficiallyutilized in sabots and shotgun wadding to retain projectile kineticenergy (FIG. 7) against loss from barrel friction and aerodynamic drag.As a projectile translates the interfacial friction is reduced throughlubrication by POSS R groups and also reduces barrel fouling.

Furthermore, the use of POSS nanostructured chemicals is very costeffective because only a small amount is needed to greatly increase thesurface area (FIG. 2). Computations indicate that a 1 wt % incorporationof POSS onto a material provides a billion nm²/g increase in surfacearea. Thus the incorporation of small amount of FOSS is botheconomically and technically effective at dominating surface area.

EXAMPLES General Process Variables Applicable to all Processes

As is typical with chemical processes, there are a number of variablesthat can be used to control the purity, selectivity, rate and mechanismof any process. Variables influencing the process for the incorporationof nanostructured chemicals (e.g. POSS, POMS, POS) into plasticsincludes the size, polydispersity, topology, composition, and rigidityof the nanostructured chemical. Similarly the molecular weight,polydispersity and composition of the polymer system must also bematched with that of the nanostructured chemical. Finally, the kinetics,thermodynamics, and processing aids used during the compounding processare also tools of the trade that can impact the loading level and degreeof enhancement resulting from incorporation of nanostructured chemicalsinto polymers. Blending processes such as melt blending, dry blending,milling, grinding, and solution mixing blending are all effective inutilizing nanostructured chemicals. Continuous, semicontinuos, and batchprocess methods of incorporation can be used.

Methods for application include master batching, mixing, blending,milling, grinding, and thermal or solvent assisted methods includingspraying and vapor deposition. Masterbatching is particularly desiredbecause it affords automated and continuous production and consequentcost saving advantages. The incorporation of a nanostructured chemicalinto or onto a particle polymer favorably impacts a multitude ofphysical properties.

Example 1 Masterbatch Dispersion of Particles

POSS trisilanols were added to metallic particles by dissolving the POSSin dicholoromethane followed by addition of the metal particle powder.The solvent was then recovered under reduced pressure and the solid washeated to promote bonding of the POSS to the surface through Si—O—M bondformation.

POSS trisilanols were added to thermoplastic polymers by meltcompounding followed by addition of metallic particles and additionalmelt compounding. Similarly POSS trisilanols and metallic powders wereadded to a polymer during melt compounding followed by extrusion andpelletizing of the final composition. A striking observation was anincreased bright whiteness of the systems utilizing POSS trisilanols andnanoscopic titanium dioxide as compared to formulations without the POSSsurface modification (FIG. 8).

In addition to increased brightness, the use of POSS trisilanolsresulted in finer particle sizes and more uniform distributions thancould be obtained without nanoscopic surface modification. Thedispersion level of the POSS within the polymer with and without themetallic particle is provided as evidence of the ability to createmasterbatches with enhanced dispersion (FIG. 9).

Specific combinations of POSS with polymer and fillers are necessary toobtain optimal dispersions and masterbatch concentrations. For exampleheptaisoOctyl POSS trisilanol #SO1455, TrisilanolisoButyl POSS #SO1450,or OctaisoButyl POSS #MS0825, are most preferably utilized withpolyethylene, polypropylene and related polyolefins. While masterbatchconcentrations of POSS at greater than 20 wt % can be utilized, loadinglevels of 0.1 wt % POSS are effective at creation of stable dispersions.

Masterbatches of polar thermoplastics such as polyamides, polyethers,polycarbonates, polyesters, and polyurethanes preferably utilizetrisilanolphenyl POSS #SO1458 or trisilanolisoOctyl POSS #SO1455. Whilemasterbatch concentrations of POSS at greater than 20 wt % can beutilized, loading levels of 0.1 wt % POSS are also effective at creationof stable dispersions.

Masterbatches containing 75% by weight of inorganic solid such a Gd₂O₃can be achieved while maintaining high levels of dispersion andprocessability into molded articles.

Example 2 Topographic Control of Molded Plastics

Masterbatches containing 5 and 10 wt % Octaisobutyl POSS (#MS0825) andpolypropylene (PP) were prepared utilizing a continuous co-rotating twinscrew extruder with an L:D ratio of 40:1. Surface topographymeasurements were made by hot pressing the extrudate between cleansilicon wafers and conducting tapping mode surface topography. Therelative surface roughness from incorporation of 10% MS0825 POSSincreased four fold (from 0.61 nm for PP) (FIG. 10) to 2.23 nm for thePOSS-PP (FIG. 11). The topographical measurements verify the control ofsurface roughness at the nanoscopic length scale and the uniformincorporation of MS0825 POSS throughout the PP in 1.5-50 nm domains.

Example 3 Surface Friction Control

Surface topology control necessarily renders control over surfacefriction properties. Nanoscale surface friction studies were performedvia AFM in lateral force mode (LFM) on 1 μm×1 μm scan size for masterbatches of POSS in thermoplastic polymers. Relative coefficient offriction (μ) is defined as the ratio of the total lateral friction force(F_(f)) to the total normal force (F_(N)). In LFM AFM, the surface isscanned in the direction perpendicular to the long axis of thecantilever and the probe experiences a friction force in the directionopposite to the scanning direction. The relative coefficient of frictionfor PP, and PP masterbatches containing 5 wt. % and 10 wt. % MS0825 POSSis shown in Table 1. The incorporation of 10 wt. % MS0825 POSS in PPresults in an almost 60% reduction in relative coefficient of friction(COF). The reduction in surface friction renders polymers containingPOSS useful for low friction textiles and molded articles.

TABLE 1 Comparisons of adhesion and friction for PP MS0825 POSSmasterbatches Relative Adhesive Force (nN) % COF Composition COFIntercept Force Curve Reduction PP control 0.17 37.77 30.76 — PP/5%MS0825 POSS 0.14 20.57 17.35 18 PP + 10% MS0825 POSS 0.07 26.29 15.02 59

Example 4 Friction Reduction of Projectiles

As illustrated in FIG. 7, nanostructured chemicals can be utilized todecrease the surface area and subsequent coefficient of friction fordissimilar surfaces. This application is particularly attractive forapplication as low friction projectiles.

A series of 0.22 cal rimfire and 0.50 cal true-to bore bullets werecoated with various POSS nanostructured chemicals and their ballisticproperties were measured. Given the use of lead and copper in bullets,POSS cages functionalized with silanol groups and thiol groups werefound to be particularly adherent to the bullets due to the formation ofstrong bonds to the metal.

Each of the bullets was cleaned prior to coating to remove particulates.The bullets were then dipped into a solution containing dichloromethaneand dissolved POSS. The preferred POSS systems that are useful for suchapplication are heptaisoOctyl POSS trisilanol (#SO1455) andheptaisoOctylPOSSpropylthiol (#TH1555) in solution loadings from 0.1 wt% to 10 wt %. The bullets were then air dried.

Ballistic testing was conducted using a fire-arm which was cleanedbefore and after firing. The purpose of the cleaning was to examine theamount of residue and to avoid cross contamination. A noticeableimprovement in both bullet velocity and reduction of bullet drop wasobserved as well as reduction in barrel residue (fouling) (Table 2).Such enhancements are of great value to sportsmen, law enforcement andthe military.

TABLE 2 Comparison of ballistics for 0.22 caliber bullets Bullet Caliber0.22 Ave. Vel. Std deviation Coating ft/sec ft/sec Trajectory dropControl 1046 70.75 bullets dropped 7″ at 60 yds TH1555 1064 35.45bullets dropped 4.5″ at 60 yds SO1455 1062 14.24 bullets dropped 4.5″ at60 yds

Example 5 Friction Reduction of Sabots

The use of nanoscopic POSS to attain low friction polymer surfaces isalso desirable for sabots to reduce energy loss. A wide series of POSSpolyolefin and polyamide masterbatches were prepared and injectionmolded into shotgun wads. The wads were then loaded with 1.25 oz of #2steel shot using same-lot, factory controlled powder loadings. Therounds were then fired and both shot velocity and pattern were measured(Table 3). The findings indicated and increase in shot velocity andsignificantly tighter shot pattern. Such enhancements are of great valueto sportsmen, law enforcement and the military. The combination of POSScoated projectiles and low friction sabots is also envisioned.

TABLE 3 Comparison of ballistics for 12 gauge steel-shot shotgun wads.Ave. Shot Velocity Resulting Shot Composition ft/sec pattern Wad flightdistance LDPE Control 1342 modified choke LDPE 5 wt % 1364 equivalent towad traveled 20 yds further MS0825 full choke LDPE 5 wt % 1364equivalent to wad traveled 18 yds further SO1450 full choke LDPE 5 wt %1356 modified-full wad traveled 10 yds further MS0830 choke pattern

While certain representative embodiments and details have been shown forpurposes of illustrating the invention, it will be apparent to thoseskilled in the art that various changes in the methods and apparatusdisclosed herein may be made without departing from the scope of theinvention which is defined in the appended claims.

What is claimed is:
 1. A method for modifying the surface or interfacialproperties of a material comprising the steps of: (a) providing apolymer or particulate material selected from the group consisting of(i) a polymer selected from the group consisting of acrylics,carbonates, epoxies, esters, silicones, polyolefins, polyethers,polyesters, polycarbonates, polyamides, polyurethanes, polyimides,phenolics, cyanate esters, polyureas, resoles, polyanalines,fluoropolymers, silicones, styrenics, amides, nitriles, olefins,aromatic oxides, aromatic sulfides, esters, and ionomers or rubberypolymers derived from hydrocarbons and silicones, and (ii) a particulateselected from the group consisting of metals, metal alloys, oxides,ceramics, ceramic alloys, microtubes, nanotubes, inorganic compounds,organic compounds, man-made materials, and naturally occurringmaterials; and (b) incorporating a nanostructured chemical selected fromthe group consisting of POSS, POS, and POMS with the material by mixing;wherein the surface roughness of the mixture is increased or decreasedby at least twenty-five percent relative to the surface roughness of theunmixed material.
 2. The method of claim 1, wherein the surface area ofthe material is modified by the nanostructured chemical.
 3. The methodof claim 1, wherein the volume of the material is modified by thenanostructured chemical.
 4. The method of claim 1, wherein thenanostructured chemical reinforces the material at a molecular level. 5.The method of claim 1, wherein the nanostructured chemical is reactivelyblended into the mixture.
 6. The method of claim 1, wherein thenanostructured chemical is nonreactively blended into the mixture. 7.The method of claim 1, wherein the material is a projectile or a sabot,and the surface roughness of the material is decreased.
 8. The method ofclaim 1, wherein a physical property selected from the group consistingof lubricity and friction is improved by incorporating thenanostructured chemical into the material.
 9. A method for dispersing aparticulate into a polymer, comprising the steps of: (a) providing apolymer selected from the group consisting of acrylics, carbonates,epoxies, esters, silicones, polyolefins, polyethers, polyesters,polycarbonates, polyamides, polyurethanes, polyimides, phenolics,cyanate esters, polyureas, resoles, polyanalines, fluoropolymers,silicones, styrenics, amides, nitriles, olefins, aromatic oxides,aromatic sulfides, esters, and ionomers or rubbery polymers derived fromhydrocarbons and silicones; (b) providing a particulate materialselected from the group consisting of metals, metal alloys, oxides,ceramics, ceramic alloys, microtubes, nanotubes, inorganic compounds,organic compounds, man-made materials, and naturally occurringmaterials; and (c) incorporating a nanostructured chemical selected fromthe group consisting of POSS, POS, and POMS with the polymer andparticulate by mixing; wherein the nanostructured material facilitatesdispersion of the particulate in the polymer.
 10. The method of claim 9,wherein the nanostructured chemical reinforces the polymer at amolecular level.
 11. The method of claim 9, wherein the nanostructuredchemical reactively bonds with the polymer or the particulate.
 12. Themethod of claim 9, wherein the nanostructured chemical is nonreactivelyblended into the mixture.